Electrode, particularly sole electrode for m-type electron tube



Feb. 8, 1966 G. HENRY-BEZY ET AL 3,234,424

ELEGTRODE, PARTICULARLY SOLE ELECTRODE FOR M-TYPE ELECTRON TUBE Filed April 50', 1962 Quouovllfl/own l .ueneuanmm FIG.3

INVENTORSI G-HENRYBEZY i Ph. GAUTIER United States Patent O 3,234,424 ELECTRODE, PARTICULARLY SQLE ELECTRODE FOR M-TYPE ELECTRON TUBE Georges Henry-Bezy and Philippe Gautier, Paris, France, assignors to CSF-Compagnie Generale de Telegraphie Sans Fil, Paris, France Filed Apr. 30, 1962, Ser. No. 191,081 Claims priority, application France, May 4, 1961,

0,69 16 claims. (ci. sis- 106) The present invention relates to M-type electron tubes, that is to those comprising an emissive cathode directing an electron beam within the space comprised between a pair of parallel electrodes, carried at different potentials, and means enabling the creation within this space of a magnetic field of which the lines of force are simultaneously perpendicular to the direct-current electric field existing therein and to the trajectory or path of the electron beam.

More particularly, the present invention relates to the ysole structure of such tubes, that is, to that of the electrodes of the aforementioned pair which is more negative.

It is known that at the beginning of the development of these types of tubes, the sole was traversed by an undesirable current of which the appearance was explained by the bombardment of the sole by certain electrons of the beam deviated by the magnetic field applied to the tube, such bombardment producing a secondary emission of which certain electrons could even reach the collector of the tube. It the quantity of these secondary emission electrons is greater than that of the primary electrons absorbed, there exists within the sole an inverse or backward current. This inverse current exercised in the prior art structures an unfavorable iniiuence on the output of the tubes and on the heating of the electrodes, and the interest which existed to suppress the same became all too obvious relatively rapidly.

It has already been proposed heretofore to suppress or at least strongly reduce the sole current by providing within the surface of the latter a network of parallel grooves, slits or ridges. According to the U.S. Patent 2,992,360, assigned to the assignee of the present application, these grooves may have a direction parallel to the lines of force of the magnetic field, that is, transverse with respect to the direction of the extension of the sole. According to the U.S. Patent 2,992,354, also assigned to the assignee of the present application, these grooves may also be longitudinal, that is, extend in the direction of propagation of the beam. In both of these cases, as disclosed in the aforementioned two patents, there has been provided a uni-directional network of grooves to form traps for the secondary electrons.

The object of the present invention is an arrangement of grooves which permits an improvement in the obtained results from the point of view of capture of secondary electrons by the sole, and consequently, of suppression or strong reduction of the sole current.

Accordingly, it is an object of the present invention to provide a sole structure which obviates the shortcomings of the prior art mentioned hereinabove.

It is another object of the present invention to provide a sole structure utilizable in M-type electron discharge tubes which yassures an improved eiiiciency of the tube.

Still another object of the present invention resides in the provision of a sole structure which effectively precludes the occurrence of backward currents within the sole structure by maintaining the quantity of primary electrons absorbed larger than that of the secondary electrons emitted.

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Still a further object of the present invention resides in the provision of a sole structure provided with a bi-dimensional network of secondary electron suppressing means so as to improve the over-all performance of the tube.

These and other objects, features vand advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawing which shows, for purposes of illustration only, several embodiments in accordance with the present invention, and wherein FIGURE l is a partial perspective View of a first embodiment of a sole structure in accordance with the present invention;

FiGURE 2 is a partial longitudinal cross sectional View through a sole structure in accordance with the present invention, and

FIGURE 3 is a partial plan view of the embodiment illustrated in FIGURE 2.

Referring now to the drawing wherein like reference numerals are used throughout the various views to designate like parts, the sole structure according to the present invention is provided with crossed channels forming a bi-dimension-al network. For example, there may be provided a series of parallel longitudinal grooves, crossing another series of transverse parallel grooves. The sole thus assumes a configuration as shown in FIGURE l in which reference numeral I represents in perspective the body of the sole, the arrow 2 indicating the direction of the longitudinal grooves, the arrow 3 that of the transverse grooves and reference numeral 4 the fingers or pins formed by the intersection of the grooves.

According to a modified embodiment shown in longitudinal cross sectional view in FIGURE 2 and plan View in FIGURE 3, the lingers 4 may be inclined in the direction opposite to the propagation of the beam, as indicated in FIGURE 2 by arrow 5.

Additionally, the longitudinal section of the fingers 4 may be triangular instead of rectangular as shown in FIGURE l. Such an arrangement and construction of the fingers 4 further improves the efiicacy of the traps provided within the sole.

The dimensions of the system will be suchvthat the channels and fingers do not impart to the sole any retarding property with respect to the utilized wave length. For example, for -a tube operating with-in the band of 23 centimeters there may be used grooves of 0.7 millimeter width, the cross section of the fingers being 0.6 x 0.6 mm.2 and the height thereof being between 2 and 2.5 millimeters. Such a sole behaves practically as a smooth surface with respect to the propagation of the utilized wave.

Actual tests and experiments by applicants have clearly demonstrated that with a certain sole, identical otherwise and operating within a tube of the same characteristics, there still existed a backward sole current which was rather important if the sole was provided simply with channels or grooves in a single dimension according to the prior art technique whereas with crossed channels, in accordance with the present invention, not only the inverse or backward sole current was completely annulled but also the quantity of primary electrons absorbed by the sole was larger than that of second-ary electrons effectively leaving the sole which caused circulation within the sole of a small forward current which in no way harmed the performance of the tube.

While we have shown and described two embodiments in accordance with the present invention, it is understood that the same is not limited thereto, but is susceptible of many changes and modifications within the spirit and scope thereof, as known to a person skilled in the art, and we therefore do not wish to be limited to the details shown and disclosed herein, but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.' y y We claim:

1. A sole electrode, especially for an M-type electron tube, provided at the surface thereof with a network of bi-dimensional secondary electron suppressing means extending in two distinct directions effectively forming traps for secondary electrons.

2. A sole electrode, especially for an M-type electron tube, provided at the surface thereof with two series of grooves to effectively form traps for secondary electrons, the grooves in each series being mutually substantially parallel, and both series crossing one another substantially at right angle.

3. A sole electrode especially for an M-type electron tube provided at the surface thereof with two series of grooves to effectively form traps for secondary electrons, the grooves in each series being mutually substantially parallel, and both series crossing one another substantially at right angle, the two series being, respectively, substantially parallel to the longitudinal and transverse direction of said electrode.

4. A sole electrode, especially for an M-type electron tube, provided at the surface thereof with a bi-dimensional network of pins, and the spaces between the pins effectively forming traps for secondary electrons.

5. A sole electrode, especially for an M-type electron tube, provided at the surface thereof with mutually crossing rows of pins forming a bi-dimensional network, whereby the spaces between said pins effectively form traps for secondary electrons.

6. A sole electrode, especially for an M-type electron tube, provided at the surface thereof with mutually crossing rows of pins crossing each other substantially at right angle and forming a bi-dimensional network, whereby the spaces between said pins effectively form traps for secondary electrons.

'7. A sole electrode, especially for an M-type electron tube, provided at the surface thereof with mutually crossing rows of pins crossing each other substantially at right angle and forming a bi-dimensional network, whereby the spaces between said pins effectively form traps for secondary electrons, said rows extending, on the one hand, in the longitudinal direction and, on the other, in the transverse direction of said electrode.

8. A sole electrode, especially for an M-type electron tube, provided at the surface thereof with a bi-dimensional network of pins, and the spaces between the pins effectively forming traps for secondary electrons, said pins being so dimensioned as to confer to said electrode characteristics substantially devoid of delaying properties for the propagation of electromagnetic microwave energy propagating therealong substantially at the velocity of the propagation of light.

9. A sole electrode, especially for an M-type electron tube, provided at the surface thereof with a bi-dirnensional network of pins, and the spaces between the pins effectively forming traps for secondary electrons, said pins being substantially normal to said electrode.

10. A sole electrode, especially for an M-type electron tube, provided at the surface thereof with a bi-dimensional network of pins, and the spaces between the pins effectively forming traps for secondary electrons, said pins being substantially parallel to each other and inclined to said surface.

11. A sole electrode, especially for an M-type electron tube, provided at the surface thereof with a bi-dimensional network of pins, and the spaces between the pins effectively forming traps for secondary electrons, said pins being substantially parallel to each other and inclined to said surface in a direction substantially opposite to the normal direction of movement of the electron flow near said surface.

12. A sole electrode, especially for an M-type electron tube, provided at the surface thereof with a bi-dimensional network of pins, Vthe spaces between the pins effectively forming traps for secondary electrons and said pins being of substantially rectangular shape in the longitudinal cross section thereof.

13. A sole electrode, especially for an M-type electron tube, provided at the surface thereof with a bi-dimensional network of pins, the spaces between the pins effectively forming traps for secondary electrons and said pins being of substantially triangular shape in the longitudinal cross section thereof.

14. In an electron tube having a source of primary electrons and provided with an electrode structure delimiting an interaction space, means for guiding said electrons in a first direction past said electrode structure including means for generating within said interaction space an electric field and a magnetic field crossed with said electric field thereby guiding said electrons perpendicularly to both of said fields, the improvement essentially consisting of `second means for substantially preventing the escape of secondary electrons from said electrode structure due to the impact thereagainst of said primary electrons, said second means including bi-dimensional network means extending in two distinct directions effectively constituting secondary electron traps.

15. In an electron tube having a source of primary electrons and provided with an electrode structure delimiting an interaction space, means for guiding said electrons in a first direction past said electrode structure including means for generating within said interaction space an electric field and a magnetic field crossed with said electric field thereby guiding said electrons perpendicularly to both of said fields, the improvement essentially consisting of second means for substantially preventing the escape of secondary electrons from said electrode structure due to the impact thereagainst of said primary electrons, said second means including bi-dimensional network means extending in two distinct directions and effectively constituting secondary electron traps and operable to leave substantially unaffected the non-retarding characteristic of said electrode structure at the utilized frequencies.

16. In a multi-electrode electron discharge device, an electrode structure comprising, at the surface thereof, a network of bi-dimensional secondary electron suppressing means extending in two distinct directions and effectively forming traps for secondary electrons emitted from said electrode.

References Cited by the Examiner UNITED STATES PATENTS 2,939,037 5/1960 Jepsen 313-106 X 2,992,360 7/1961 Reverdin 313-106 X JOHN W. HUCKERT, Primary Examiner.

ARTHUR GAUSS, DAVID J. GALVIN, Examiners. 

15. IN AN ELECTRON TUBE HAVING A SOURCE OF PRIMARY ELECTRONS AND PROVIDED WITH AN ELECTRODE STRUCTURE DELIMITING AN INTERACTION SPACE, MEANS FOR GUIDING SAID ELECTRONS IN A FIRST DIRECTION PAST SAID ELECTRODE STRUCTURE INCLUDING MEANS FOR GENERATING WITHIN SAID INTERACTION SPACE AN ELECTRIC FIELD AND A MAGNETIC FIELD CROSSED WITH SAID ELECTRIC FIELD THEREBY GUIDING SAID ELECTRONS PERPENDICULARLY TO BOTH OF SAID FIELD, THE IMPROVEMENT ESSENTIALLY CONSISTING OF SECOND MEANS FOR SUBSTANTIALLY PREVENTING THE ESCAPE OF SECONDARY ELECTRONS FROM SAD ELECTRODE STRUCTURE DUE TO THE IMPACT THEREAGAINST OF SAID PRIMARY ELECTRONS, SAID SECOND MEANS INCLUDING BI-DIMENSIONAL NETWORK MEANS EXTENDING IN TWO DISTINCT DIRECTIONS AND EFFECTIVELY CONSTITUTING SECONDARY ELECTRONS TRAPS AND OPERABLE TO LEAVE SUBSTANTIALLY UNAFFECTED THE NON-RETARDING CHARACTERISTIC OF SAID ELECTRODE STRUCTURE AT THE UTILIZED FREQUENCIES. 